This invention relates to magnesia carbon bricks and more particularly, to magnesia carbon bricks for use as the linings of various furnaces and their associated hot metal handling devices and a method for preparing such bricks.
Magnesia carbon bricks have been in the lime-light as the materials for the linings of various furnaces and their associated hot metal handling devices in recent years because such bricks have excellent corrosion and spalling resistance properties and the application range of such bricks is increasing. However, the above-mentioned excellent properties of such bricks have not been fully utilized because such bricks encounter difficulties in the preparation thereof.
Among the difficulties, one most important difficulty is that since a substantial difference in specific gravity is present between magnesia and graphite which are principal components of magnesia carbon brick and graphite generally has poor wettability, these components cannot be easily admixed and molded and accordingly, a magnesia carbon brick cannot be obtained with a sufficient density. In order to compensate for the poor wettability of graphite, a binder such as pitch, tar or the like is generally employed in the mixture of magnesia clinker and carbon. However, such binder emits an offensive smell to give discomfort to the operator and/or chap the operator's skin and as a result, the admixing operation cannot be performed in an effective manner.
In order to overcome the difficulties encountered in the preparation of prior art magnesia carbon bricks by the conventional methods, in place of the conventional pitch or tar, the use of phenol resins as the binder has been proposed.